Health & Lifestyle Calculators
14 tools in this collection — free, instant, and private in your browser.
Health and lifestyle calculators cover the clinical and behavioral metrics that help individuals and caregivers make informed decisions about everyday health. Some of these tools perform the same calculations used in clinical settings, making them valuable for understanding lab results, medication dosing, and physiological measurements in plain terms.
Clinical chemistry calculators address specific diagnostic needs. The Anion Gap Calculator helps identify the cause of metabolic acidosis by measuring unmeasured anions in blood chemistry panels. The Corrected Calcium Calculator adjusts a raw serum calcium result for low albumin levels, which is essential because albumin binds calcium and low albumin can make calcium appear falsely low. The Creatinine Clearance Calculator using the Cockcroft-Gault equation estimates kidney filtration rate from age, weight, and creatinine, while the eGFR Calculator using the CKD-EPI 2021 equation provides a more accurate estimate that does not require body weight. Mean Arterial Pressure reflects average perfusion pressure throughout the cardiac cycle and is used to assess circulatory adequacy.
Diabetes management tools bridge lab results and daily experience. The A1C to Estimated Average Glucose Calculator converts the percentage-based A1C result into a familiar milligrams-per-deciliter number that matches what a home glucose monitor reports, making it easier to contextualize what a given A1C means day to day.
Lifestyle and habit calculators quantify the cumulative effect of behaviors that are easy to underestimate. The Pack-Years Calculator summarizes lifetime smoking exposure in a single number used to assess disease risk. The Smoking Cost Calculator translates daily cigarette consumption into annual and lifetime financial costs. The Blood Alcohol Content Calculator estimates BAC from drinks consumed, body weight, and time elapsed. The Sleep Debt and Jet Lag Recovery Calculators help you understand how sleep deficits accumulate and how to recover from disrupted circadian rhythms.
These calculators are educational tools designed to help you understand and discuss health information. Always consult a qualified healthcare provider for diagnosis and treatment decisions.
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| Tool | What it does |
|---|---|
| A1C to Estimated Average Glucose Calculator | Convert HbA1c percentage to estimated average glucose (eAG) in mg/dL or mmol/L using the ADA consensus formula. |
| Alcohol Units Calculator | Calculate alcohol units in any drink from volume and ABV. Compare to UK weekly guidelines. |
| Anion Gap Calculator | Calculate the serum anion gap from sodium, chloride, and bicarbonate. With optional albumin correction for hypoalbuminaemia. |
| Blood Alcohol Content (BAC) Calculator | Estimate blood alcohol content (BAC %) using the Widmark formula. Enter drinks consumed, body weight, sex, and time elapsed. |
| Body Surface Area Calculator | Calculate body surface area (BSA) using the Mosteller formula — used in drug dosing and oncology. |
| Dog Medication Dose Calculator | Calculate the total dose for a dog from a mg/kg dosing rate and body weight. For reference only — always follow your vet's prescription. |
| Estimated Average Glucose to A1C Calculator | Convert estimated average glucose (eAG in mg/dL or mmol/L) back to an approximate HbA1c percentage using the ADA consensus formula. |
| Jet Lag Recovery Calculator | Estimate how many days it will take to recover from jet lag based on the number of time zones crossed. |
| Pack-Years Calculator | Calculate your smoking pack-years — the standard measure of lifetime tobacco exposure. |
| Sleep Bedtime Calculator | Enter your desired wake-up time and find the ideal bedtimes based on 90-minute sleep cycles. Wake up refreshed, not groggy. |
| Sleep Debt Calculator | Calculate your weekly sleep debt by comparing your actual sleep to the recommended 8 hours per night. |
| Smoking Cost Calculator | See the cumulative financial cost of smoking over years. Enter your daily cigarette count, pack price and number of years for a chart of money spent. |
| Weekly Screen Time Calculator | Calculate your total weekly screen time and see how it compares to health recommendations. Enter daily average screen time. |
| eGFR Calculator (CKD-EPI 2021) | Estimate glomerular filtration rate (eGFR) using the 2021 race-free CKD-EPI creatinine equation. For screening only — confirm with your doctor. |
Frequently asked questions
- What is the difference between creatinine clearance and eGFR?
- Both estimate kidney function but use different formulas. Creatinine clearance calculated by the Cockcroft-Gault equation requires age, weight, sex, and serum creatinine and has been used in clinical practice for decades, particularly for medication dosing. The eGFR calculated by the CKD-EPI 2021 equation uses the same variables but without body weight and is considered more accurate for staging chronic kidney disease. Your doctor may use one or both depending on the clinical context.
- How many drinks does it take to reach the legal driving limit?
- The legal limit in most US states is a BAC of 0.08 percent, but the number of drinks required to reach that level varies considerably with body weight, sex, the time over which drinks are consumed, and whether food was eaten. A 120-pound person may reach 0.08 after two drinks, while a 200-pound person may require four or more. The Blood Alcohol Content Calculator accounts for these variables, but it provides an estimate, not a guarantee, and the safest choice is always not to drive after drinking.
- What does a pack-year measurement mean clinically?
- A pack-year is defined as smoking one pack of 20 cigarettes per day for one year. Someone who smoked half a pack per day for 20 years would have 10 pack-years. Clinical guidelines commonly use 20 or more pack-years as a threshold for lung cancer screening recommendations. The metric gives clinicians a standardized way to compare lifetime smoking exposure regardless of the specific pattern of use.